The prefixed and postfixed brachial plexus: a review with surgical implications.

The definition of a pre and postfixed brachial plexus is varied in the literature, which results in inconsistent conclusions for various studies. As anatomical variation is important both during clinical evaluation and surgical procedures of the brachial plexus, a review of this literature was performed. Based on our review, variation in the contribution to the brachial plexus is more the rule than the exception. These variations may lead to deviation from the expected dermatome distribution as well as differences in the motor innervation of muscles of the upper limb. Such variations may predispose patients to certain pathology such as thoracic outlet syndrome and may alter surgical approaches to the brachial plexus.